JP2003152428A - Small antenna and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sustain the reliability inexpensively and to prevent radiation efficiency from lowering. SOLUTION: The small antenna comprises a core material 2a, i.e., a hard linear member, imparted with a specified shape corresponding to the resonance characteristics, a conductor film 2b having an electric conductivity higher than that of the core material 2a and covering at least a part of the outer surface of the core material 2a, and a basic body 3 for holding the core material 2a covered with the conductor film 2b while surrounding the outer surface thereof tightly wherein the film thickness d of the conductor film 2b is the skin depth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small antenna used for a mobile terminal or the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 26 is a diagram showing a schematic configuration of a conventional small antenna used in a mobile terminal. FIG. 26 (a)
The antenna 301 has a radiating portion 301a shaped like a meander, and the radiating portion 301a is surrounded by a dielectric 301b. A terminal portion 301c for connecting to the circuit board is connected to the radiation portion 301a. Similarly, FIG.
In the small antenna 302 shown in FIG. 6 (b), the helical radiation portion 302a is surrounded by the dielectric material 302b. A terminal portion 302c is connected to the radiating portion 302a.

In order to improve the radiation efficiency of the antenna, the electric conductivity of the radiating parts 301a and 302a must be made as high as possible. That is, the radiating portions 301a and 302
When the electric conductivity of a is low, the ratio of the electric power supplied to the radiating portions 301a and 302a to be lost as thermal energy is high. Therefore, it is desirable that the electric conductivity be as high as possible.

[0004]

As described above, the antenna conductor needs to have good radiation efficiency, but it is also important that the antenna conductor be sufficiently connected to the circuit board when it is mounted on the circuit board. Requirements.

The present invention has been made in view of the above, and an object thereof is to provide a small antenna capable of improving radiation efficiency. Another object of the present invention is to provide a small antenna that can be firmly mounted on a circuit board and a manufacturing method thereof.

[0006]

In order to achieve the above object, in a small antenna according to claim 1, a bent linear core and at least a part of an outer surface of the core are covered, A conductor film having a higher electric conductivity than the electric conductivity of the core material, and an antenna conductor formed by the conductor film.

In the small conductor according to claim 2, the conductor film has the following equation δ = √ (2 / (σ · μ · ω)) where σ: electric conductivity of the conductor μ: conductor Permeability ω: having a film thickness equal to or greater than the skin depth δ specified by the angular frequency.

According to a third aspect of the small antenna, the core material is made of a copper alloy, and the conductor film is made of copper.

According to a fourth aspect of the present invention, there is provided a small antenna having an antenna conductor formed of a radiating portion for transmitting and receiving radio waves and a terminal portion for connecting the radiating portion to a circuit board. And a connection film for improving the solder characteristic is covered, and the connection film is not formed on the radiation part.

Further, in the miniature antenna according to a fifth aspect of the invention, the connection film has a lower electric conductivity than the electric conductivity of the layer on the surface side of the radiating portion.

Further, in the small antenna according to the sixth aspect, the connection film is formed by solder plating.

According to a seventh aspect of the small antenna, the connection film covers the entire surface of the terminal portion.

Further, in the compact antenna according to the eighth aspect, the radiating portion and the terminal portion are formed by punching a metal plate.

According to a ninth aspect of the present invention, in the small antenna, the radiating portion is covered with a dielectric, and the terminal portion is exposed from the dielectric.

According to a tenth aspect of the present invention, in the small-sized antenna, the antenna conductor is formed of a core material and a conductor film covering at least an outer surface of the core material corresponding to the radiation portion. Is formed of a material having higher electrical conductivity than the core material.

According to the eleventh aspect of the present invention, in the small antenna, the conductor film has the following equation δ = √ (2 / (σ · μ · ω)) where σ: electric conductivity of the conductor μ: conductor Permeability ω: having a film thickness equal to or greater than the skin depth δ specified by the angular frequency.

According to the twelfth aspect of the method of manufacturing a small antenna, a metal plate is punched out of an antenna conductor having a radiation part for transmitting and receiving radio waves and a terminal part for connecting the radiation part to a circuit board. A punching step formed by processing, a coating step of coating the radiation portion with a dielectric, a connection film forming step of selectively forming the connection film with respect to the terminal portion using the dielectric as a mask, It is characterized by including.

In the method for manufacturing a small antenna according to a thirteenth aspect, in the punching step, the metal plate is punched into a shape that further includes a frame supporting the antenna conductor to form the connection film. The method further comprises a cutting step of cutting the antenna conductor from the frame after the step.

According to a fourteenth aspect of the present invention, in the method of manufacturing a small antenna, in the punching step, the metal plate is punched into a shape in which the frame and the terminal portion are separated from each other. .

Further, in the method for manufacturing a small antenna according to claim 15, in the punching step, the metal plate is punched into a shape in which the frame and the terminal portion are continuous, and the connection film is formed. Before the step, a preliminary cutting step for separating the frame and the terminal portion is provided.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a small antenna and a manufacturing method thereof according to the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a perspective view showing a schematic configuration of a small antenna according to a first embodiment of the present invention. In FIG. 1, the small antenna 1 includes an antenna conductor A having a radiation portion 2 and a terminal portion 4 that are bent in a meandering shape, and surrounds the radiation portion 2 without any gap,
The base body 3 is made of a dielectric material and has an outer shape of a rectangular parallelepiped.
A terminal portion 4 protruding from the dielectric base 3 is formed at one end of the radiating portion 2.

FIG. 2 is a cross-sectional view of the small antenna 1 shown in FIG. In FIG. 2, the radiating portion 2 is surrounded by the base body 3 without any gap. The base 3 is made of a dielectric material. The radiating portion 2 is a core material 2 formed by punching out a linear hard metal plate material having spring properties such as phosphor bronze or iron.
The conductor film 2b is formed by plating a material having high electric conductivity such as pure copper, which has higher electric conductivity than the core material 2a, on the outer surface of a. The conductor film 2b is the core material 2a.
Is formed all around and over the entire length. Conductor film 2
The thickness d of b is the skin depth δ.

Generally, when a high-frequency current flows through a conductor, the current is concentrated and flows from the surface of the conductor to a region of skin depth δ due to the skin effect. The skin depth δ is a depth defined as δ = √ (2 / (σ · μ · ω)). Here, σ is the electrical conductivity of the conductor, μ is the magnetic permeability of the conductor, and ω is the angular frequency (2π × frequency).

Therefore, by setting the film thickness d of the conductor film 2b of the radiation portion 2 shown in FIG.
Most of the electric current passes through the inside of the conductor film 2b having high electric conductivity,
Since it does not pass through the core material 2a, the radiation efficiency of the antenna can be sufficiently increased. In this case, since the core material 2a is made of a hard and springy material, it is possible to prevent the core material 2a from being deformed at the time of manufacturing the antenna, and it is possible to enhance the reliability of the radiation section 2.

FIG. 3 is a diagram showing a structure in the vicinity of the terminal portion 4 of the antenna conductor A. As shown in FIG. Further, FIG. 4 is a cross-sectional view of the terminal portion 4 shown in FIG. The core material 2a of the radiation portion 2 of the antenna conductor A is made of phosphor bronze, and
b is made of pure copper. The terminal portion 4 is shown in FIG.
As shown in FIG.
A multi-layer film including a conductor film 4b of (nickel) and a conductor film 4c of gold (Au) is metallized. Here, Ni of the conductor film 4b is provided to improve the adhesion (wetting) with Au. Further, Au of the conductor film 4c is for rust prevention and improves solder wettability.

Here, in the example shown in FIG. 3A, the tip portion 4d of the terminal portion 4 elastically and firmly contacts the mounting portion 5a of the conductor pattern 5 formed on the substrate 6, Are electrically connected. Figure 3
In the example shown in (b), the tip portion 4d of the terminal portion 4 is soldered to the mounting portion 5a of the substrate 6 and electrically connected by the solder 7.

The radiating portion 2 in the base 3 described above has
Although only one conductor film 2b was formed, the invention is not limited to this.
You may laminate | stack the layer which consists of a metal with high conductivity.

The conductor film 2b can prevent the radiation efficiency from decreasing to some extent without covering the entire outer surface of the core material 2a. FIG. 5 shows a mode of the conductor film 2b covering the outer surface of the core material 2a of the radiating section 2, and FIG. 6 is a diagram showing changes in the radiation efficiency with respect to the conductor film 2b of each configuration shown in FIG.

FIG. 5 (a) is a sectional view showing a case where no conductor film is formed on the outer surface of the core material 2a, and FIG. 5 (b) shows a conductor film formed only on one long side region of the core material 2a. 5C shows a cross-sectional view of the case, and FIG. 5C shows a cross-sectional view when the conductor film is formed only on the two long side regions of the core material 2a.
(D) shows a sectional view in the case where a conductor film is formed on the entire outer surface of the core material 2a. Further, points P1 to P4 in FIG.
Indicates the radiation efficiency (%) in the configurations shown in FIGS. 5A to 5D, respectively. The cross-sectional area of the core material 2a is 100 μm × 200 μm.

As shown in FIG. 6, when the conductor film is not provided (FIG. 5A), the radiation efficiency is 100% when the radiation portion 2 is made of pure copper. It will be about 38%. Further, when the conductor film is provided only on one long side (FIG. 5B), the radiation efficiency is 70.
It will be about%. Further, when the conductor film is provided only on the two long sides (FIG. 5C), the radiation efficiency is about 89%. When a conductor film is provided on the entire outer surface of the core material 2a (FIG. 5D), the radiation efficiency is almost 100%, which is almost the same as the radiation portion made of copper.

From this result, it can be seen that the antenna of this example has the following advantages. When a conductor film made of pure copper is provided on the entire outer surface of the core material 2a, it is possible to achieve substantially the same radiation efficiency as in the case where the radiator 2 is made of pure copper. Moreover, since the core material 2a is formed of phosphor bronze, the radiating portion 2 has sufficient and sufficient hardness and spring properties to maintain high reliability. Further, when a material having high electric conductivity such as gold or silver is applied to the conductor film, the radiation efficiency can be more effectively increased. In this case, the amount of the radiation portion 2 used can be reduced as compared with the case where all the radiation portions 2 are formed of expensive gold or silver, and thus high radiation efficiency can be obtained at low cost.

Further, even when the conductor film 2b is formed only on a part of the core material 2a (FIGS. 5B and 5C), the skin effect maintains a relatively high radiation efficiency. be able to.

Generally, when the radiation portion 2 is formed in a meandering shape or a helical shape, the radiation effect is lower than that of the linear shape, but this problem is solved by providing the conductor film 2b like the antenna of this example. it can.

Next, a method for manufacturing the above-mentioned small antenna will be described. In the manufacture of the small antenna 1, first, the core material 2a bent in a meander shape having a cross section of 100 μm × 200 μm is formed by punching out a sheet metal of phosphor bronze. Then, the outer surface of the core material 2a is plated with copper to form the conductor film 2b.

After that, the copper-plated antenna conductor A is inserted into an injection molding die, and then a dielectric material (ceramics-resin composite material) is injection-molded into a rectangular parallelepiped to form the base 3. At this time, the terminal portion 4 is arranged outside the base body 3. When the terminal portion 4 is metallized, the conductor material is sequentially coated after the conductor film 2b is formed.

In the first embodiment described above, the film thickness d of the conductor film 2b is the skin depth δ, but it is desirable that the film thickness d be larger than the skin depth δ. However, it may be thin. Further, the conductor film 2b may be formed on a part of the outer surface of the core material 2a. In addition, you may make it combine the structure which changes the film thickness d. In any case, the skin effect can be obtained rather than the case where the conductor film 2b is not provided at all, and the spring property of the antenna conductor A can be maintained and the radiation efficiency can be prevented from lowering.

Further, in the first embodiment described above, the radiating portion 2 is formed in a meandering shape, but the present invention is not limited to this, and it may have any shape such as a helical shape. Furthermore, in the above-described first embodiment, the cross-sectional shape of the radiating portion 2 is rectangular, but the present invention is not limited to this, and the cross-sectional shape of the radiating portion 2 is a circle (see FIG. 7).
It may be an arbitrary shape such as a reference) or an ellipse. In this case, for example, as shown in FIG. 7, the conductor film 12b is formed on the outer surface of the core material 12a, and the thickness d thereof is defined as the skin depth δ.

(Second Embodiment) In the second embodiment, a method of manufacturing an antenna will be described. First, a conductor pattern 110 as shown in FIG. 8 is formed by punching or etching a thin metal plate (punching step).

The conductor pattern 110 has a thickness of 0.1 m.
Rectangular flat plate antenna conductor 1 made of a metal plate of about m
12 and a frame 114 (supporting part) surrounding the same, and the space between the radiation part 112a of the antenna conductor 112 and the frame 114 is the radiation part 112a of the antenna conductor 112.
A plurality of support pieces 116 formed on both side edges of the antenna conductor 112 at appropriate intervals, a feeding terminal portion 118 and a ground terminal portion 120 formed on one end edge of the radiation portion 112a of the antenna conductor 112, and the radiation portion 112a. The fixed terminal portion 122 formed on the other end edge of is connected.

In this example, the radiating portion 112a and the terminal portions 118, 120 and 122 form the antenna conductor 112. Reference numeral 124 is an opening formed by punching, and 126 is a positioning hole.

Although it is possible to omit the frame 114, it is easier to handle the conductor pattern 110. The fixed terminal portion 122 is provided as needed and can be omitted. Also, ground terminal 1
20 may be omitted depending on the type of antenna conductor (for example, unnecessary when the antenna conductor is a meandering antenna conductor or the like).

Next, the conductor pattern 110 is formed as shown in FIG.
~ Positioning pin 129 of the lower die 128B as shown in FIG.
Is set to the molds 128A and 128B. That is, the frame 114, the outer end sides of the support pieces 116, and the outer end sides of the terminal portions 118, 120, 122 are sandwiched between the split surfaces of the upper die 128A and the lower die 128B, and the radiating portion of the antenna conductor. 112a, a part on the inner end side of each support piece 116, and a part on the inner end side of each terminal portion 118, 120, 122 are set so as to be positioned in the cavity 130 of the molds 128A, 128B.

In this state, a dielectric material obtained by mixing resin and ceramic powder is injected into the cavity 130 (coating step). After molding, the molds 128A and 128B are opened and the resin molded body integrated with the conductor pattern 110 is taken out.
It becomes like FIG.

After the molded body is taken out of the mold, it is placed in a plating bath for solder plating (connection film forming step). After that, the support piece 116 is cut along both side surfaces of the base body 132 made of a dielectric material, and each terminal portion 118,
If the outer ends of 120 and 122 are separated from the frame 114 and bent, the small antenna 13 as shown in FIG.
6 can be obtained. In the small antenna 136, the radiation portion 112 a of the antenna conductor 112 is embedded in the base body 132, and the power feeding terminal portion 11 is provided from one end surface of the base body 132.
8 and the ground terminal portion 120 are projected, and the fixed terminal portion 122 is projected from the other end surface of the surface mount type. Solder plating is applied to each of the terminals 118, 120, 122 as a connection film.

(Third Embodiment) FIG. 14 shows a third embodiment. The third embodiment differs from the second embodiment in that the conductor pattern 11 is provided with no support piece 116.
This is a point using 0. In this case, the upper and lower molds 128A,
The radiating part 11 of the antenna conductor 112 is divided by the 128B split surface
2a, the edge of the fixed terminal portion 122 side, and the power feeding terminal portion 118.
And the ground terminal part 120 is sandwiched.

(Fourth Embodiment) FIG. 15 shows a fourth embodiment. FIG. 15 shows a state when the molding process is completed.
The difference between the fourth embodiment and the second embodiment is that the conductor patterns 110 in which the respective terminal portions 118, 120, 122 are not connected to the frame 114 are used. In this embodiment, since the terminal portions 118, 120, 122 are separated from the frame 114 in advance, it is easy to plate the entire peripheral surface (cut surface) of the terminal portion.

(Fifth Embodiment) FIG. 16 is a perspective view showing a schematic configuration of a small antenna according to a fifth embodiment of the present invention. In FIG. 16, the small antenna 201 has an antenna conductor B having a rectangular radiating portion 202, and a dielectric base body 203 that surrounds the radiating portion 202 without any gap and has a rectangular parallelepiped outer shape. Radiator 2
At both ends of 02, terminal portions 204 protruding from the base body 203
~ 206 are formed.

FIG. 17 shows the small antenna 2 shown in FIG.
It is a transverse cross-sectional view of 01. Here, FIG. 17A is a cross-sectional view of the radiating portion 202 and the base body 203.
(B) is a cross-sectional view of the terminal portion 204. FIG. 17 (a)
In, the radiating portion 202 is surrounded by the base body 203 without any space. In addition, in FIG. 17B, the terminal portion 204
Is a metal piece integrally formed with the radiating portion 202, and a connection film 204a is plated on the surface thereof. Here, the connection film 204a is formed to improve solder wettability, and its electric conductivity is lower than that of the metal plate.
Further, the terminal portions 205 and 206 are metal pieces integrally formed with the radiating portion 202, similarly to the terminal portion 204, and the surface thereof has connection films 205a and 206 similar to the connection film 204a.
a is plated.

Next, mounting of this antenna on the substrate will be described. FIG. 18 shows the terminal portion 204 of the antenna.
It is a figure which shows the structure of the vicinity. As shown in FIG. 18, the terminal portion 204 is soldered to the mounting portion 5a of the conductor pattern 5 formed on the substrate 6, and is thereby electrically connected. Here, the terminal portion 204 is
It is joined to the mounting portion 5a via the connection film 204a. The connection film 204a can improve the adhesion (wetness) between the terminal portion 204 and the conductor pattern 5, and as a result, the fillet F is formed in the portion where the connection film 204a is present, and the substrate 6 of the antenna conductor B is formed. The bond to is strong. The same applies to the terminal portion 205 and the terminal portion 206.

Next, a method of manufacturing the small antenna 201 will be described with reference to FIGS. In manufacturing the small antenna 201, first, a copper alloy plate is punched to form a metal plate 207 shown in FIG. Metal plate 2
07 has a frame 207a, and has a radiating portion 202 and terminals 204 to 206 inside the frame 207a. The terminals 204 to 206 are connected to the radiator 202 and the frame 207a. Further, the radiating part 202 and the frame 207a are connected by a plurality of supporting parts 208.

Subsequently, the metal plate 207 is inserted into the injection molding die, and then the dielectric material (ceramic-resin composite material) is injection-molded into a rectangular parallelepiped to form the base body 203 (FIG. 20). At this time, the terminal portions 204 to 206 are arranged outside the base body 203. Further, a metal plate 207 obtained by injection molding of the base body 203 is solder-plated in a full bath (FIG. 21). Here, the base body 203 functions as a mask, and the frame 207a and the terminal portions 204 to 20.
6 is selectively solder-plated to form a connection film 204a on the terminal portion 204. The same applies to the terminal portions 205 and 206.

Next, the plurality of supporting portions 208 are attached to the base body 203.
Along with the frame 207a and the terminal portion 20
By cutting the boundary between 4 and 206, the frame 207
a and the supporting portion 208 are separated, and the small antenna 201
Can be obtained.

According to this method of manufacturing a small antenna, the terminal portions 204 to 206 can be selectively plated, so that the deterioration of the antenna characteristics due to the adhesion of solder to the radiation portion 202 can be prevented and the terminal portions 204 to 206 can be prevented. The adhesion (wetting) of 206 to the conductor pattern 5 can be improved.

Further, by using the base body 203 as a solder plating mask, the masking step can be omitted, the manufacturing can be facilitated, and the manufacturing cost can be reduced.

If the radiation portion 202 can be sufficiently fixed by connecting the terminal portions 204 to 206 and the frame, the supporting portion 208 can be omitted. Terminal parts 204-2
FIG. 22 shows a metal plate in which the radiating portion is fixed by connecting 06 and the frame. In FIG. 22, the metal plate 209 has a frame 209a, and has a radiating portion 202 and terminals 204 to 206 inside the frame 209a. Terminal part 2
Numerals 04 to 206 denote the radiating portion 202 and the frame 209a.
The radiator 202 is fixed inside the frame 209a. For other configurations and manufacturing methods,
This is similar to the case of the metal plate 207.

On the contrary, the metal plate may be punched by connecting the frame only by the supporting part and separating the terminal part and the frame. FIG. 23 shows a metal plate when the terminal portion and the frame are separated. In FIG. 23, the metal plate 217 has a frame 217a, and the radiation part 2 is provided inside the frame 217a.
02 and terminal portions 214 to 216. The terminals 214 to 216 are connected to the radiator 202 and separated from the frame 217a. Further, the plurality of support parts 218 are connected to the radiation part 202 and the frame 217a, and the radiation part 202 and the terminal part 2 are connected.
14 to 216 are fixed inside the frame 217a.

Regarding the method of manufacturing this metal plate 217 into a small antenna, as in the case of the metal plate 207 described above, the radiation portion 202 is injection molded to form the base body 203, and the terminal portions 214 to 216 are further formed. After performing the solder plating, the supporting portion 218 is cut. A small antenna manufactured using the metal plate 217 is shown in FIG. The small antenna 211 shown in FIG. 24 has an antenna conductor C having a rectangular radiating portion 202, and a base body 203 surrounding the radiating portion 202 without any gap and having a rectangular parallelepiped outer shape. Terminal portions 214 to 216 protruding from the base body 203 are formed at both ends of the radiating portion 202. Here, the terminal portions 214 to 216 are metal pieces integrally formed with the radiating portion 202, and the surface thereof is plated with a connection film.

As described above, the terminal portion 214 is punched separately from the frame 217a and then the connection film 214a is formed by solder plating. Therefore, the entire terminal portion 214 including the end face 214b is formed. The connection film 214a can be formed on the surface of the. Therefore,
All the surfaces of the terminal portion 214 including the end surface 214b are covered with the connection film 214a, so that the adhesion (wetting) to the solder is improved. As a result, when this antenna is soldered to the board 6, as shown in FIG.
The solder fillet F is formed up to the end surface 214b of 14 and is more firmly soldered. Terminal part 215,
Similarly, in 216 as well, all the surfaces including the end surface are covered with the connection film, and the adhesion (wetting) to the conductor pattern is obtained.
Can be improved.

In forming the metal plate 217, the metal plate may be punched by separating the terminal portion and the frame as described above, or may be punched by connecting the terminal portion and the frame. Alternatively, the connection film may be formed up to the terminal surface of the terminal portion by cutting the gap between these before plating the connection film. Even in this case, the solder fillet is formed up to the end surface of the terminal portion when soldering is performed.

Further, the terminal portion may be bent to the lower side of the base so as to be in contact with the substrate. FIG. 25 shows the terminal portion 2.
14 is a cross-sectional view showing a cross section of a terminal portion 214 when 14 is bent to the lower side of the base body 203 and soldered to the substrate 6. FIG.
Also in this small antenna, the terminal surface 214 of the terminal portion 214 can be obtained by performing the solder plating on the terminal portion 214 after separating the terminal portion 214 from the frame 217a.
The entire surface of the terminal portion 214 including b can be covered with the connection film 214a. As a result, even in this small antenna, the solder fillet F is extended to the end face 214b of the terminal portion 214.
Are formed and are firmly soldered to the circuit board 6.

The metal plate is not limited to phosphor bronze.
Instead, various alloys can be used. For example, 42
alloy (modulus of elasticity = 145 (× N³ / Mm² ),
Tensile strength = 588 to 735 (N / mm² )), Cu0.
15Cr0.1Sn (Furukawa Electric Co., Ltd. model number = EFTEC
-6) (modulus of elasticity = 119 (× N³ / Mm² ), Tension
Strength = 353 to 431 (N / mm² ), Elongation ≧ 5
(%), Fatigue strength = 137 (N / mm² )), Cu0.
1Fe0.03P (Furukawa Electric Co., Ltd. model number = EFTEC-
7) (Longitudinal elastic modulus = 119 (× N³ / Mm² ), Tensile strength
S = 353-431 (N / mm² ), Elongation ≧ 5 (%),
Fatigue strength = 137 (N / mm² )), Cu0.3Cr
0.25Sn0.2Zn (Furukawa Electric Co., Ltd. model number = EFT
EC-64T) (longitudinal elastic modulus = 127 (× N³ / Mm
² ), Tensile strength = 539 to 637 (N / mm²), Growth
≧ 5 (%), fatigue strength = 265 (N / mm² )), Cu
2.5Ni0.6Si0.5Zn0.03Ag (Furukawa Electric
Kou Co., Ltd. model number = EFTEC-23Z) (modulus of elasticity = 1
28 (× N³ / Mm² ), Tensile strength = 620-740
(N / mm ² ), Elongation ≧ 5 (%), fatigue strength = 275
(N / mm² )) And the like are preferable.

The above-mentioned chemical composition ratio shows the standardized weight%.

If necessary, a conductor film having a high electric conductivity is applied to these metal plates.

[0065]

As described above, according to the present invention,
The antenna conductor having higher reliability and high radiation efficiency can be realized at low cost.

Further, according to the present invention, the terminal portion of the antenna conductor can be firmly soldered to the feeding electrode or the like of the circuit board, and the deterioration of the radiation characteristic due to the connection film can be avoided, so that the radiation characteristic is not impaired. This has the effect of improving the mountability of the antenna.

Further, according to the present invention, since the terminal portion of the antenna conductor is connected to the circuit board through the connection film covering the entire surface of the terminal portion, the bonding strength between the terminal portion and the circuit board is further improved. There is an effect that can be.

Further, according to the present invention, it is possible to provide a small antenna having a good mountability on a circuit board by a simple manufacturing method.

Further, according to the present invention, since the connection film is formed by using the dielectric covering the radiating portion as a mask, it is possible to provide a small antenna having both radiation characteristics and mountability by a simple manufacturing method. It has the effect of being able to.

Further, according to the present invention, since the connection film is selectively formed with respect to the terminal portion by using the dielectric as a mask, the adhesion between the terminal portion and the circuit board is good and the radiation efficiency is small. The effect of being able to be manufactured easily and cheaply is exhibited.

Further, according to the present invention, since the end portion of the terminal portion is opened and the connection film is formed on all the surfaces of the terminal portion, the terminal portion and the circuit board can be further strengthened. The small antenna that can be joined can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a small antenna that is Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing the configuration of the small antenna shown in FIG.

3A and 3B are diagrams showing a connection state between the antenna and the circuit board shown in FIG. 1, and FIGS. 3A and 3B are diagrams showing different states.

4 is a transverse cross-sectional view showing the configuration of a terminal portion of the antenna conductor shown in FIG.

FIG. 5 is a cross-sectional view showing a form of a ratio of a conductor film provided on the outer surface of the core material.

FIG. 6 is a diagram showing a change in radiation efficiency with respect to the ratio of the conductor film shown in FIG.

FIG. 7 is a diagram showing a case where a radiating section has a circular cross section.

FIG. 8 is a plan view showing a conductor pattern including an antenna conductor used in the second embodiment of the present invention.

9 is a horizontal sectional view showing a state in which the conductor pattern shown in FIG. 8 is set in a mold.

FIG. 10 shows WW line, XX line, and FIG.
It is sectional drawing which shows the part in the YY line.

11 is a cross-sectional view showing a portion taken along line ZZ shown in FIG.

FIG. 12 is a plan view showing a state in which the base body integrated with the conductor pattern shown in FIG. 8 is taken out from the mold.

FIG. 13 shows an example of a small antenna manufactured by the manufacturing method shown in the second embodiment, (A) is a plan view,
(B) is a side view, (C) is a rear view, and (D) is a front view.

FIG. 14 is a horizontal sectional view showing the conductor pattern shown in the third embodiment set in a mold.

FIG. 15 is a plan view showing the conductor pattern shown in the embodiment shown in the fourth embodiment.

FIG. 16 is a diagram showing a schematic configuration of a small antenna that is Embodiment 5 of the present invention.

17 is a cross-sectional view showing the configuration of the small antenna shown in FIG.

FIG. 18 is a perspective view (a) and a cross-sectional view (b) showing a state at the time of mounting in the vicinity of a mounting portion of the antenna conductor shown in FIG.

FIG. 19 is a view (No. 1) showing the method for manufacturing the small antenna shown in FIG. 16;

FIG. 20 is a view (No. 2) showing the method for manufacturing the small antenna shown in FIG. 16;

FIG. 21 is a view (No. 3) showing the method for manufacturing the small antenna shown in FIG. 16;

FIG. 22 is a view showing a metal plate when the radiation portion is fixed by connecting the terminal portion and the frame.

FIG. 23 is a diagram showing a metal plate when the terminal portion and the frame are separated.

FIG. 24 is a diagram (a) showing a small antenna manufactured using the metal plate shown in FIG. 23, and a sectional view (b) of a terminal portion showing a state in which the small antenna is soldered to a circuit board.

FIG. 25 is a cross-sectional view showing a terminal portion when the terminal portion is bent to the lower side of the base body and soldered to the substrate.

FIG. 26 is a diagram showing a schematic configuration of a conventional small antenna.

[Explanation of symbols]

1, 136, 201, 211 Small antennas A, B, C, 112 Antenna conductors 2, 112a, 202 Radiating parts 2a, 12a Core materials 2b, 4b, 4c, 12b Conductor films 3, 132, 203 Base bodies 4, 204 to 206, 214 to 216 Terminal portion 4d Tip portion 5,110 Conductor pattern 5a Mounting portion 6 Substrate 114, 207a, 209a, 217a Frame 116 Support piece 118 Power supply terminal portion 120 Ground terminal portion 122 Fixed terminal portion 124 Opening portion 128A, 128B Mold 130 Cavity 134 excess portions 204a, 205a, 206a, 214a, 215a,
216a Connection film 207, 217, 209 Metal plate 208, 218 Support portion 214b End surface

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroki Hamada             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. (72) Inventor Masayuki Isawa             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. (72) Inventor Takahiro Ueno             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. F term (reference) 5J046 AA04 AA19 AB06 AB13 PA04                       PA07 QA02 QA08

Claims (15)

[Claims] 1. A bent core material, and a conductor film that covers at least a part of an outer surface of the core material and has a higher electric conductivity than that of the core material. A small antenna having an antenna conductor. 2. The conductor film has the following equation δ = √ (2 / (σ · μ · ω)) where σ: electric conductivity of the conductor μ: permeability of the conductor ω: skin specified by angular frequency The small antenna according to claim 1, which has a film thickness equal to or greater than a depth δ. 3. The core material is formed of a copper alloy,
The small antenna according to claim 1, wherein the conductor film is made of copper. 4. An antenna conductor having a radiating portion for transmitting and receiving radio waves and a terminal portion for connecting the radiating portion to a circuit board, wherein the terminal portion is covered with a connection film for improving solder characteristics. However, the small antenna is characterized in that the connection film is not formed on the radiation part. 5. The small antenna according to claim 4, wherein the connection film has a lower electric conductivity than that of a layer on the front surface side of the radiating portion. 6. The small antenna according to claim 4, wherein the connection film is formed by solder plating. 7. The small antenna according to claim 4, wherein the connection film covers the entire surface of the terminal portion. 8. The small antenna according to claim 4, wherein the radiating portion and the terminal portion are formed by stamping a metal plate. 9. The small antenna according to claim 4, wherein the radiation portion is covered with a dielectric, and the terminal portion is exposed from the dielectric. 10. The antenna conductor is formed of a core material and a conductor film covering at least an outer surface of the core material corresponding to a radiation portion, and the conductor film is formed of a material having higher electric conductivity than the core material. It is characterized by the above-mentioned.
Small antenna described in. 11. The conductor film has the following formula δ = √ (2 / (σ · μ · ω)) where σ: electric conductivity of the conductor μ: permeability of the conductor ω: skin specified by angular frequency The small antenna according to claim 10, having a film thickness equal to or greater than a depth δ. 12. A punching step of forming a metal plate by a punching process to form an antenna conductor having a radiation portion for transmitting and receiving radio waves and a terminal portion for connecting the radiation portion to a circuit board, and the radiation portion is made of a dielectric material. A method of manufacturing a small antenna, comprising: a coating step of coating; and a connection film forming step of selectively forming the connection film on the terminal portion using the dielectric as a mask. 13. The punching step further includes a step of punching the metal plate in a shape that further includes a frame supporting the antenna conductor, and cutting the antenna conductor from the frame after the connection film forming step. The method for manufacturing a small antenna according to claim 12, further comprising: 14. The method of manufacturing a small antenna according to claim 13, wherein in the punching step, the metal plate is punched into a shape in which the frame and the terminal portion are separated from each other. 15. In the punching step, the metal plate is punched into a shape in which the frame and the terminal portion are continuous, and preliminary cutting is performed to separate the frame and the terminal portion before the connection film forming step. The method for manufacturing a small antenna according to claim 13, further comprising steps.